Process for manufacturing a low density, foam-fiber product

Claim 1

A PROCESS FOR MANUFACTURING A LOW DENSITY, FOAMFIBER PRODUCT WHICH COMPRISES FORMING A LOW-BONDED FIBER SHEET, SAID SHEET HAVING AN APPARENT DENSITY IN THE RANGE OF ABOUT 1.0 TO 2.3, A DRY TENSILE SUM PER POUND IN THE RANGE OF ABOUT 0.04 TO 0.23, AND A WET TENSILE SUM PER POUND OF ABOUT 0.0005 TO 0.0060; SATURATING SAID SHEET WITH AN AQUEOUS DISPERSION TO SUBSTANTIALLY RELEASE THE FIBER-TO-FIBER BONDS IN SAID SHEET, SAID SATURANT CONTAINING MINOR AMOUNTS OF A WET GEL-FORMING MATERIAL, A HEATACTIVATABLE GAS-FORMING AGENT, AND A HEAT-ACTIVATABLE INSOLUBILIZATION AGENT FOR SAID WET GEL-FORMING MATERIAL; GRADUALLY HEATING SAID SATURATED SHEET IN A MOIST ATMOSPHERE FIRST TO A TEMPERATURE SUFFICIENT TO ACTIVATE SAID GASFORMING AGENT AND THEREBY FORM WITH SAID GEL-FORMING AGENT A FOAM DURING WHICH FORMATION THE INDIVIDUAL FIBERS IN SAID SHEET ARE CAUSED TO SEPARATE FROM EACH OTHER AND BECOME SUSPENDED IN THE WALL OF THE CELLS COMPRISING SAID FOAM; THEN FURTHER INCREASING THE TEMPERATURE OF SAID FOAM-FIBER SUSPENSION TO ABOUT 190*F. TO 260*F. TO ACTIVATE SAID INSOLUBILIZATION AGENT TO CAUSE SAID FOAMED GEL-FORMING AGENT TO INSOLUBILIZE AND RETAIN SAID SEPARATED FIBERS EMBEDDED WITHIN THE WALLS OF THE FOAMED STRUCTURE; AND SUBSEQUENTLY DRYING SAID FOAM-FIBER COMBINATION TO SET THE FOAMED STRUCTURE IN ITS EXPANDED CONDITION.